Safety cans of the type with which this invention is most commonly used (but without excluding vessels of other shapes or construction) have a seamless cylindrical body with an integral dome-shaped top. Near the periphery of the top there is an upwardly projecting spout commonly used both for filling the can with liquid or for pouring contents from the can into another receptacle such as, for example, the fuel tank of an industrial or other tractor, as well as machinery or fuel burners at some fixed location. This spout, instead of having a removable screw cap commonly used on smaller cans, such as used for lawn mowers, small boats and the like, has a closure cap suspended from the end of an overhanging lever which is spring biased to hold the spout cover firmly and tightly against the top of the spout.
In use, such vessels are generally lifted vertically and, while being so held in one hand, are then grasped by the other hand at the bottom and tilted. The extent of the tilt is pretty much gauged by the weight of the can, and when the spout is in proper relation for transfer of liquid from the safety can to the receiving vessel, the spring biased cover is opened to allow pouring from the safety can to the receiving vessel to proceed.
Various arrangements have heretofore been provided for effecting the opening of the cover. Certain prior art patents have contemplated the provision of a lifting handle pivoted to the top of the can in such manner that when the can has been lifted and is being rocked from a vertical position toward a horizontal position, the lifting handle will pivot from a plane normal to the plane of the top of the can to a plane approaching one parallel with the top of the can, and such relative change of position of the handle effects an opening of the spout cover. One serious object to this is that the spout cover starts to open as the vessel starts to tilt, whereas it is desirable, to prevent spillage and waste, to bring the pouring spout with the vessel tilted to an angle, according to whether the can is full, perhaps nearly half empty or below half full, into proper relation with the filling spout of the receiving vessel and then independently throttle the opening of the pouring spout. In other words, with the tilting of the can automatically effecting the opening of the pouring spout, proper or exact aim with respect to the receiving vessel without excessive spillage is difficult to achieve. In some environments spillage may be dangerous as well as wasteful. The problem is not unlike one encountered by a novice in pouring liquid from an open topped vessel into another vessel without the use of a funnel in the receiving vessel.
Others have sought to avoid the foregoing difficulty by providing a lifting handle associated with an independent spout covering operating linkage which, however, requires the relaxing, if not the complete momentary release, of the handle from which the weight of the front or top end of the tilted can receives its support, or the tilted can is perhaps rested against the tank which is to receive liquid while one changes one's grip. So far as I am aware such devices have not been commercially accepted.